Telegraph printer



July 19, 1932. WEAVER TELEGRAPH PRINTER Filed June '7, 1950 INVENTOR AWE A VE R ATTORNEY Patented July 19, 1932 ire PHONE AND STATES PATENT,

ALLAN WEAVER, or roar wnsnrneron, NEW YORK, assreuon T AMERICAN mama,

TELEGRAPH. COMPANY, a oonronArron' or'niiw YORK I rnnnannrn PRINTERApplication ruse June 7', 1930. Serial No. 459,762.

This invention relates to receivers for.

selective telegraph systems and particularly for those employ ng theBaudot code, that is, those in which the character signals consist oftwo difierent electrical conditions, such as'permutations of positiveand negative impulses or current and no current, extending through adefinite number, usually five, of time intervals or units. The featuresof the invention relate more particu-, larly to the socalled start-stopsystems, wherein the rotating member -:or distributor of the receiver iskept in step or in phase with the signals by start-stop mechanism thatarrests the rotating member at the end of the signal period or duringspacing intervals between signals and again initiates its operation inresponse at the beginning of each signal.

The present invention is adapted to aselec tor mechanism for a printerof the type disclosed and described in U. S. Patent 1,745 ,633, grantedto S. Morton and H. L. Krum on February 4, 1930. ticularly adaptedforstart-stop systems and is one which canbe mechanically operated underthe control of a single magnet.

Heretofore in printers wherein the selector mech anism was operated by asingle magnet, the magnet was of the neutral type, but it is an objectof this equipped with a magnet of the polarized type in an efficient andeconomical manner. -Another object is to utilize a normal the outputcircuit of a'current rectifier for operating the polarized magnet inresponse to received signal impulses.

According to the present invention an alternating current power supplyfor operatthe transformer onto two opposite points 0 a ll heatstonebridge arrangement, thearms of which each include a suitable rectifiersuch as disclosed in S. Patent 15 19549, granted to J. Slepian on MarciA, 1930, for producing in a circuit connected to the other two oppositepoints on": the Wheatstone bridge, a pulsating direct current. Bypassingthe pul' sating current through a filter connected to a startinginterval or urnt' I This mechanism is par-.

invention to operate a printer 7 voltage in" ing the printer motor isimpressed through nating across the circuit,the current pulsations are.

reduced to a minimum. Connected, in series,

in the circuit are two resistances, of relatively high value and atopposite ends ofthese resistances are respectively connected twocontacts of a relay, the winding of which isconn-ected to the signaltransmissionline. The relay armature is" connected to one side of awinding of the. printer selectormagnet, the other side being connectedto the circuit at a point midway between the two resistances. Thereforethe drop .in voltage normally across each of the resistancesisutilizedfor operating the armature of the selector magnet to either of twopositions depending on the contact engaged by the relay armature inresponse to incoming signal impulses.

condenser is connected across eaohresistance for producing a suddenrise" in the current passing through the windings of the magnet I whenthe relay armature engages either contact.

will appear in Other objects and features forth, when the descriptionhereinafter set taken in conjunction with the accompanying drawing andappended claims.

Of the drawing, Fig. 1 shows theoperating circuit for the printermagnet; Fig. 2 shows asuitable type otrectifier for changing a powersupply current; and Figs. 3 and a show fragmentary views of the selectormechanism of the rinter. 1 V

The arrangements herein areshown as us ing an alternating power supplyto control the printer operations through a single polar magnet. Thepower for printing is usually suppliedfrom a 110 volt motor arranged tooperate from the electric light or power supply of this voltage.Although an alternate ing current source is shown, this source mightjust as well be of direct current furnished by a motor generator or abattery. 7

Referring to Fig. 1, the source 11 of alter current is connected througha trans former 12 to opposite points A and Got a Wheatstone bridgearrangement A, which serves as a single rectifier. Each of the arms ofthe Wheatstone bridgearrangealternating current to a direct so i mentinclude a suitable rectifier such as illuscurrent in the contactsalternately of the certain metals with respect to current flow across te junction between the metal and a chemical compound formed directlywithin the body thereof. In the case Where 2 ly deposited thereon toform two distinct withstand any desired counter-'electromotive force andthe whole assembly is clamped by means of an insulating bolt 16 betweentwo end plates 17 and 18 to which terminal concated by arrows. A moredetaileddescription of the rectifier unit may be had by referring toPatent N 0. 1,749,549.

As stated above, the induced alternating secondary windings oftransformer 12, is impressed on points A and C. When the current in thesecondary windings is flowing in an upward direction as indicated byarrow X, the path taken is from A to B, through the windings ofretardation coil 21 which has an inductance of about twenty henries,left hand contact of relay 28, through the winding of magnet 29,resistance 26, D to and back to the secondary winding. l/Vhen t isflowing in the opposite The arrangement shown requires less voltage thanthose em- The telegraph line 27 over which polar signals aretransmitted, is connected through the windings of relay 28, the armatureof which is arranged to engage its associated in response to theincoming polar signals. 'The relay armature is of the windings of theother side of the windpolar magnet 29, to the output circuit beingconnected rectifi sistances 25 and 26. In this way, when the er at apoint midway between re- 23 and from the right hand side of resistance25 in parallel. The combined current flows through the left hand contactand armature of relay 28, traverses the magnet windings in say, a rightto left direction, and then passes through resistance 26 to point '24.When the engagement with its right hand contact, as for example, afterit has just responded to an impulse of negative the potential dropacross resistance relay armature is in point 24. Therefore theCondensers are respectively connected across armature engages itscontacts.

This manner of operating magnet 29 is suitably adapted for printersdesigned to beimpulses, particularly operated by polar where theprinters are used at a receiver stations in a way transmission or" ever,it may so be used plurality of system employing onepolar signals.

neutral telegraph circuits, that is circuitsconsist of intervals ofwhere the line signals current and no current and a line relay isdesirable to improve operating margins. A line relay isparticularlydesirable in systems where th printer are'distorted in sl te printer is operated posited telegraph circuit. The line relay 28 is ofthe high speed type and requires that direct current be available at thereceiving station for operating the receiver magnet 29. The magnet 29 issuitably adapted for operation with the type of printer disclosed inPatent No. 1,745,633, supra, and for a detailed description of theoperation of this type of printer reference may be made to that directlyin a combe printed, particular parts may be identified in Patent No.1,745,633. I

he printer is especially adapted for start-stop systems wherein a startand a stop impulse, in addition to the five unit message impulse-s, arereceived to e incoming signals received by thev iape such as when recordeach characcams, such as a, b,

' mechanisms to set-up each character.

7 ends, and when it is user/,1; as

rotates in apselection set-up, is printed. The stop impulse coming inover the line, stops the rotation of the receiving shaft until the startimpulse tor the next character is received. This stopping of thereceiving mechanism after each revolution and restarting by means 0 asignal impulse sent over the line, automatically corrects once in eachrevolution for any minor variations in the speeds of difierent printers.

In Fig. 3 is shown polar magnet 29 which operates the receivingselecting mechanism of the printer. The magnet is normally in anoperated condition. When the start impulse is received the magnetarmature 32 is released and a pin 33, fixedly mounted on the armatureand acting through an intermediate pivoted lever 34, trips a stop pawllatch 35 which is pivotally mounted on the printer structure (notshown). The stop pawl latch normally engages a stop pawl 36, whichblocks a stop arm 37 from rotating. When the latch is tripped the stoppawl rotates slightly due to the pressure of the stop arm against it.The stop arm and the receiving 0, etc. (there being five in all in orderto correspond to the five unit code) rotate through power transmitted byfriction clutch 38 at the top end of the main shaft 39.

A better understanding of the operation of o the selecting mechanismwill be had by referring to Fig. l wherein the mechanism responsive toone impulse only of the transmitted signal, is shown, there being fivesuch sets of When the main shaft rotates slightly in response to thestart impulse the cams which are fixed: ly monted thereon, also rotate.\Vhen cam a, for example, rotates sufficiently, it strikes the end of acode bar operating lever 40 which is pivotally mounted on the printerstructure. At this time the armature is either operated or unoperated,depending on the polarity or nature of the message impulse received fromthe line at that time. Let it be assumed that it is an impulse that-willrestore the armature to its normally operated position as shown in thefigure. As cam a passes its code bar operating lever 4=(), the latter isrotated slightly in a counter clockwise direc tion, carrying back withit a finger or swordshaped member ll. The sword-shaped member is flatand its two arms have upturned drawn back by lever 40 the right handupturned end will strike the end of a; T

. relay, adapted right hand "end of armature extension The sword memberwill be rotated clockwise in its pivot 42, and when the cam projectionmoves to clear. lever 40, the sword member will movedownward against the{left hand lever &3. The T lever is also pivotally mounted and anypressure on its left hand end will cause code bar 44 130 move to theright as provided for by the pin in slot 45. This completes the'settingof the first code bar'for building-up the combination whichiefiects :theprintingiof the-desired character. If it is assumedthat the impulsereceived tromthe line releases the armature and the armature extension,the sword member when pulled back by the action of the selector cam arotating the code bar operating lever, will strike the letthandend ofthe armature extension and will be moved counter clockwise to engage theright end of the Tlever and move. the code bar to its nonselectedposition. In this manner each of the code bars is made'to occupy eithera selected or non-selected positionas a part of the operation ofprinting each character.

The main or cam shaft 39 rotates through one revolution for eachcharacter and the remaining four cams engage their respective code baroperating levers successively, it taking approximately three quarters ofa revolution of the shaft to "complete the set up of any combination ofcode bars. 1

In addition to the, five cams, there are in each printer five code baroperating levers, five sword members, five T levers, five code bars, butonly one armature extension bar ll which is T shaped at its free end,the ends of the cross piece being-turned up in order to be in engageablerelation with all the sword members.

' What is claimed is:

1. A telegraph receiver having a polar for printing characters inresponse to groups of signal impulses, a source of voltage, acontinuously closed circuit for said source, elements of fixed impedancein said circuit for of potential drops, and electromagnetic meansresponsive to said signal impulses for selecting one of the elementsinsaid circuit across which thempotentialdrop. occurs, in order toutilize the potential drop produced producing a plurality r'or operatingthe polar relay of said receiver local source of alternating current foroperating said rece ver, means ut1liz1ng said source for'generating ac1rcu1t,'a palr of impedance elements connected. in series 1n saidcircuit, a distant source of impulses, means responsive to saidimpulses, a polarized printer magnet connected in shunt, rst to one andthen to the direct current in said I trol device is changing other ofsaid impedance elements under the control of said impulse responsivemeans whereby the potential drop ac ross either of said impedanceelements is eflective t0 oper ate or release the armature of-saidprinter magnet in accordance with the impulses from said distant source.

3. A telegraph receiver adapted for printing characters in response togroups of signal impulses, a normally closed circuit, a local source ofalternating said receiver, means for converting said alternating currentinto a direct current in said circuit, a pair of resistances connectedin series with said circuit, a condenser connect ed across each of saidresistances, a single polarized printer magnet arranged to be connectedacross either of said resistances, an directly responsive to ancesalternately, whereby the potential drop across the resistance whichhappens to be shunted at the time, operates or releases the armature ofthe printer magnet in accordance with the signal impulses.

4. A system for operating a two-position polar relay to either of itstwo positions from a source of direct current with a current drain uponthe source of current independent of the position of the relaycomprising two impedances in series with said source and a circuitmaking-and-breaking control device connected to said relay by contactswhereby of said lmpedances and then across the other dependent upon thecontacts of said control de vice, said impedances being maintained underall operative conditions in series with said source. r

5. A system in accordance with claim 4 wherein said control device uponeach change from one of its contacts to the other is arranged toreversethe direction of voltage applied to said relay.

system in accordance with claim 4 wherein a condenser is connectedacross the terminals or each of said iinpedances to absorb the currentduring the time said confrom one position to another, the charge storedin said condenser serving to accelerate the operation of said relay. i.

In testimony whereof, I have signed my name to this specification this3rd day of June, 1930. v V ALLAN WEAVER.

current for operating

